Theoretical investigations of sandwich molecular clusters and nanowires, and their surface assembly

Ph.DDOCTOR OF PHILOSOPH

Pichia-expressed recombinant D6 and DARC negatively affect cell migration and invasion of breast cancer cells

Atypical chemokine receptor proteins are termed ‘decoy proteins’ as their binding to the respective ligands does not lead to a typical signaling pathway but intercepts the action of chemokines. This method of chemokine activity regulation may also function in tumor suppression. D6 and DARC (Duffy Antigen Receptor for Chemokines) have been reported as decoy chemokine receptors in cancer studies. Purified Pichia-expressed D6 and DARC, produced in-house, were used in cell-based studies to test their biological activities. Cell viability tests showed that recombinant D6 and DARC did not affect cell viability significantly, suggesting that they were not involved in breast cancer cell death. Wound healing assays showed that the presence of recombinant D6 or DARC at 10 μg/mL optimally inhibited the migration of breast cancer cells. ELISA showed an inverse relationship between the recombinant proteins and CCL levels in the treated cells. Migration assay using Boyden chamber demonstrated the function of the recombinant proteins in inhibiting chemotaxis activity of treated cells. Invasion assay showed the ability of the recombinant proteins in inhibiting the invasion property of treated cells. Comparison of single and combinatorial effects of the recombinant proteins showed that the combination of D6 and DARC at a 1:1 ratio (10 μg/mL) is most effective in reducing CCL levels and inhibiting the migration and invasion of treated cells. It was shown that the purified Pichia-expressed recombinant D6 and DARC are the negative regulators of breast cancer cell migration and invasion, and the inhibition effects were greater when they were used in combination

MicroSAGE is Highly Representative and Reproducible but Reveals Major Differences in Gene Expression Among Samples Obtained from Similar Tissues

Background: Serial analysis of gene expression using small amounts of starting material (microSAGE) has not yet been conclusively shown to be representative, reproducible or accurate. Results: We show that microSAGE is highly representative, reproducible and accurate, but that pronounced differences in gene expression are seen between tissue samples taken from different individuals. Conclusions: MicroSAGE is a reliable method of comprehensively profiling differences in gene expression among samples, but care should be taken in generalizing results obtained from libraries constructed from tissue obtained from different individuals and/or processed or stored differently

Adhesion of Dust Particles to Common Indoor Surfaces in an Air-Conditioned Environment

Adhesion between dust particles and indoor surfaces can lead to negative effects on human health by triggering allergic and asthmatic reactions. In this study, adhesion forces of indoor office dust and activated carbon (AC, as model soot) particles to four common indoor materials (Al, Cu, PVC, and glass) were measured by colloidal probe atomic force microscopy. Chemical analysis of office dust shows it is largely made up of oxygenated hydrophilic organic carbon material. Both metal surfaces experienced weaker dust and AC adhesion than PVC or glass by up to 2–12 times lower primarily due to the presence of attractive electrostatic forces in the latter two (non-conducting) surfaces. Dust and AC adhesion were also highly sensitive to surface roughness, with an inverse relationship between adhesion force and roughness due to the reduction in contact area between the particle and a rougher material surface. Capillary forces play only a minor or negligible role in dust and AC surface adhesion. Adhesion models utilizing a purely van der Waals approach such as the simple Hamaker model and modified Rumpf’s model are insufficient to determine the actual particlesurface contact radii and requires the accounting of non-van der Waals forces to adhesion

Effectiveness of Pandemic H1N1-2009 Vaccination in Reducing Laboratory Confirmed Influenza Infections among Military Recruits in Tropical Singapore

10.1371/journal.pone.0026572PLoS ONE610

A clinical diagnostic model for predicting influenza among young adult military personnel with febrile respiratory illness in Singapore

10.1371/journal.pone.0017468PLoS ONE63

Extractive Fermentation of Lactic Acid in Lactic Acid Bacteria Cultivation:A Review

Lactic acid bacteria are industrially important microorganisms recognized for their fermentative ability mostly in their probiotic benefits as well as lactic acid production for various applications. Nevertheless, lactic acid fermentation often suffers end-product inhibition which decreases the cell growth rate. The inhibition of lactic acid is due to the solubility of the undissociated lactic acid within the cytoplasmic membrane and insolubility of dissociated lactate, which causes acidification of cytoplasm and failure of proton motive forces. This phenomenon influences the transmembrane pH gradient and decreases the amount of energy available for cell growth. In general, the restriction imposed by lactic acid on its fermentation can be avoided by extractive fermentation techniques, which can also be exploited for product recovery